Synthesis and field-emission properties of novel hierarchical ZnO hexagonal towers

Novel hierarchical ZnO hexagonal towers were fabricated via chemical vapor deposition for the first time by adding trace Fe power in the precursor as a catalyst. The scanning electron microscopy images showed that the outside surface of novel hierarchical ZnO hexagonal towers was layer-by-layer assembly. X-ray diffraction pattern indicated that the hierarchical ZnO hexagonal towers grew preferentially along the [0 0 0 1] direction. Intense UV emission centered at 380 nm was observed at room temperature. Moreover, their field-emission properties were studied. A low turn-on electric field of 2.37 V μm−1 and high field enhancement factor of about 2691 were obtained, due to the novel layer structure and high crystalline quality. This kind of hierarchical ZnO microstructures could be a good candidate for high performance field emission devices.

► Novel hierarchical ZnO hexagonal towers (NHZOHTs) were fabricated via chemical vapor deposition, adding trace Fe power in the precursor as a catalyst.
► The growth mechanism for the NHZOHTs is due to second epitaxial growth of ZnO nanorods based on the atomic structure model and morphological evolution.
► The photoluminescence and field-emission properties were measured.
► Field-emission measurements of the NHZOHTs show a good result, due to the novel layer structure and high crystalline quality.